The present invention relates in general to a method of producing sterility in female animals, and more particularly to a method of producing sterility in female animals by an obturator implanted in the uterus of a female animal.
Cattle are customarily fattened before being slaughtered. Many different techniques have been employed such as controlling the intake of feed and controlling the type of feed consumed by the cattle.
Some cattle have been fed various drugs and chemicals to increase the weight thereof before being slaughtered. A melengestrol acetate and a progestogen have been fed to heifers to depress the estrus cycle and thereby cause a cessation of heat periods. As a consequence thereof, the body weight of the heifers is increased and the efficiency in food consumption fattens the heifers. However, this technique requires accurate dispensing of the drug on a daily basis and the heifer subjected to the drug cannot be slaughtered within 48 hours of the last administration of the drug.
Hormone implants have been used to fatten heifers for beef. The hormone implants can be discarded with the inedible parts of the carcass and thus obviate the need to feed daily a chemical or to withdraw the heifer prior to slaughter.
Dromostanolene propinate in pellet form has been implanted subcutaneously in a heifer to increase the weight thereof. The estrus cycle of the heifer is suppressed.
In an article entitled OPERATIVE CORRECTION OF PARTIAL EPIPHYSEAL PLATE CLOSURE BY OSSEOUS-BRIDGE RESECTION AND SILICANE-RUBBER IMPLANT by Robert W. Bright, appearing in The Journal Of Bone And Joint Surgery, American Volume, Volume 56-A, No. 4, June 1974, pp. 655-664, there is described an experimental study on dogs. A procedure is discussed in which silicone-rubber material is molded to fill an osseous defect. The material is applied and allowed to vulcanize.
Silicone elastomer has been used for sterilization of human females by injection into the fallopian tubes. The injected material is in a liquid state and subsequently vulcanizes to form a plug.
The patent to Dickinson, III, et al., U.S. Pat. No. 3,811,424, discloses a method of inserting a mechanical device, which clamps around the annulus of a cow's cervix. For this purpose, a clamping ring slides over and compresses against the projecting annulus of the cow's cervix. The method alters the cross-sectional configuration of the reproductive tract with subsequent stimulation and changing (or resetting) of the estrus cycle.
In the patent to Robinson, U.S. Pat. No. 3,916,898, there is disclosed a method of controlling estrus, ovulation and fertility in domestic animals by introducing into the vagina, and later removing, a sponge impregnated with a progestational compound. The patent to Haller, U.S. Pat. No. 3,690,316, discloses a cervical obturator for humans, which is made of a compressed spermicidal powder in the shape of fusiform. The powder has a wide base to serve as an obturator. The powder dissolves upon use.
The patent to Vennard et al., U.S. Pat. No. 3,779,241, discloses a preformed hollow body having thin, flexible walls which have the size and shape of the uterine cavity. A flexible, compressible, filler material fills the hollow body, whereby the walls of the hollow body will make contact with the walls of the uterine cavity. The filler material is polymerizable organosiloxane material. The patent to Bolduc et al., U.S. Pat. No. 4,119,098, discloses a dispensing apparatus for placing settable material in the uterine cavity and moving the material from the uterine cavity into the Fallopian tubes. It seals the cervical entrance to the cavity and causes expansion to conform to the slope of the uterine cavity and force the dispensed materials into the canals of the Fallopian tubes.
In the patent to Barrington, U.S. Pat. No. 4,160,446, there is disclosed a device to deliver a tubal-occluding polymer such as organosilicon rubber. The material is a foamable polymer that flows into the Fallopian tubes to occlude the tubes.
The patent to Erb, U.S. Pat. No. Re. 29,345, discloses a method for the sterilization of humans, in which a removable tip is inserted into the uterus. The tip is aligned with the uterine end of the oviduct. A curable elastomeric composition is injected through the tip into the oviduct to fill the oviduct adjacent to the uterus. The elastomer composition solidifies on the tip. The apparatus for inserting the tip in the uterus is removed and the tip is ejected by the apparatus to remain for blocking the oviduct. The apparatus is inserted through the cervical os into the uterus. The material used is silicon elastomers.
In the patent to Chvapil, U.S. Pat. No. 4,274,410, a collagen porous sponge is inserted in the upper vault of the vagina near the cervix. The sponge is preformed before it is inserted in the upper vault of the vagina near the cervix. In the patent to Chvapil, U.S. Pat. No. 4,369,773, there is disclosed a preformed collagen sponge inserted into the upper vault of the vagina to cover the cervix.
The patent to Brundin, U.S. Pat. No. 4,365,621, discloses a device for blocking the oviduct which includes a body made of hydrogels. The body swells by absorbing body fluids. The body is introduced into a cavity in its normal state and enlarges upon the absorption of body fluid to block a passage or close a cavity.
In the patent to Vickery, U.S. Pat. No. 3,991,750, issued on Nov. 16, 1976, for Dromostanolene Propinate Implant Pellet Useful For Producing Weight Gains In Animals And Suppressing Estrus In Female Animals, there is described the implant of a pellet subcutaneously in a heifer. The pellet contains dromostanolene propinate and produces an increase in weight in the heifers and suppresses the estrus cycle in the heifer.